1. Field of the Invention
The present invention relates generally to integrated circuit (IC) packages, and more specifically to containing electromagnetic interference (EMI) generated by integrated circuits.
2. Background Information
Many integrated circuits generate undesirable amounts of EMI. Typically, the xe2x80x9cnoisexe2x80x9d generated by the integrated circuit originates from the die and its connections to the pins through the package, and is coupled to the heatspreader or lid covering the die and then to the heatsink, which acts as an antenna that further radiates the EMI. As the EMI is coupled to neighboring components and integrated circuits, it interferes with their individual performance which may, in turn, affect the overall performance of a system. Because of the negative effects of EMI and because the level of acceptable radiated EMI is subject to strict regulatory limits, it is desirable to contain or suppress the EMI generated by an integrated circuit.
Some solutions take place at the printed circuit board (PCB) level. For example, one solution involves grounding the heatsink to build a Faraday cage around the EMI producing chip (e.g., a CPU). This solution typically involves the use of a grounded gasket which surrounds the chip and makes contact with the heatsink. However, the effectiveness of this solution is dependent on having good contact between the gasket and the heatsink and between the heatsink and the chip lid. Because of the gasket contacts with ground on the top layer of the PCB, the routing of the pin escapes on the top layer may be very difficult or even impossible. In such a situation, the PCB may need additional layers which increases the cost of the PCB. Furthermore, the gasket itself represents an additional cost and potential point of failure, as it is a separate part that must be added to the PCB.
EMI solutions at the IC package level are often ignored because the main concerns at that level are signal integrity and functionality. It would be beneficial to have an EMI solution at the package level because it would help reduce the need for xe2x80x9cdownstreamxe2x80x9d or add-on solutions.
An apparatus comprises an integrated circuit package comprising a first EMI containment configuration and a second EMI containment configuration disposed around the first EMI containment configuration. The first and second EMI containment configurations are grounded by at least one ground plane of the package.
Additional features and benefits of the present invention will become apparent from the detailed description, figures and claims set forth below.